2.0 Analysis 2.1 General This investigation included an examination of environmental, technical, human, and operational factors as well as mechanical aspects of this aircraft, its component parts, and their service life and history. No indication was found of any malfunction or pre-existing mechanical defect with the aircraft, its engine, or its systems that could have caused or contributed to the accident. As a result, this analysis focusses on selected operational aspects of the accident. 2.2 Aircraft Control Witnesses reported that the first three approaches and the touchdown appeared to be normal and controlled. This would suggest that the pilot was not experiencing any abnormal aircraft control function and that he was capable of controlling the aircraft. In concert with the reported wind and water conditions, the brief accident sequence observed by the village people is consistent with two possible scenarios or a combination of the two: on initial touchdown in a left-crosswind condition, the left float struck a swell or wave which forced the aircraft into an attitude that the pilot was not able to control before the float(s) or wing dug into the water and caused the aircraft to overturn; or the aircraft was upset by a wind gust at or shortly after touchdown which the pilot was not able to control before the float(s) dug into the water and caused the aircraft to overturn. Technical examination of the rudder trim system revealed that it was not significantly damaged, and there was no indication that the trim cables had been disturbed on impact causing the trim to move. Furthermore, due to its design, impact to the trim tab itself would not have changed the trim indication in the cockpit. Although the rudder trim tab and rudder trim indicator both had captured indications of nearly full right rudder trim setting, it could not be determined if this setting had been deliberately selected by the pilot, or when he had selected it. Almost full right rudder trim is not normally employed by pilots for landing on water and likely would not go unnoticed by a pilot. Such a trim setting can be used in the take-off and climb phases without adverse effect on the flying characteristics of the aircraft. Had it been so set during the approach and landing phase, it would not have rendered the aircraft uncontrollable. 2.3 Water Conditions Witnesses reported that the water surface conditions were rough when the aircraft attempted to land. Therefore, it is most likely that the pilot made the first three approaches to assess the wind and water conditions and to determine the best water surface on which to finally land. Experienced floatplane pilots find that wind and water conditions in Kincolith are generally challenging to land in because of the water and topography surrounding Nass Bay. On the day of the accident, several local environmental conditions, such as exposed mud flats, unpredictable and inconsistent water chop, and conflicting wind and swell directions, compounded the difficulties faced by the occurrence pilot. It is likely that the earlier inflow wind conditions had created a significant southwesterly swell in the Portland Inlet and Nass Bay, and that swell would have intensified over the shallow bar off Kincolith. At the time of the accident, the wind had reportedly changed to the northwest. The direction of the approaches that the aircraft was seen to fly was apparently parallel to the swell and would have presented a left crosswind situation for the pilot. While it would have been possible for the floatplane to land uneventfully in such conditions, the level of risk would have been elevated and the attendant margin for error reduced. 2.4 Right Front Seat Personnel Restraint Adjustment When the right front seat personnel restraint is worn correctly, the shoulder strap passes over the occupant's right shoulder and chest, and attaches to the seat belt buckle fitting at the left hip. In this accident, the buckle was found in the centre of the lap belt, indicating that the buckle would have been near the middle of the passenger's abdomen, not on her left side. With such lap belt adjustment, the shoulder harness would have passed over the right side of her torso and upper right arm. As a result, in the event of any significant deceleration, it is most likely that her upper body would not have been restrained effectively because she would have rolled out from the shoulder strap. In this accident, with a rapid overturn, it is conceivable that the passenger could have then slipped out from the loose personnel restraint while it remained fastened. The adjustment procedure for the lap belt portion of the right front seat's personnel restraint is different from the lap belt of the cabin seats because it has to allow for the correct placement of the shoulder strap at the left hip. It is possible that the practice of adjusting the cabin lap belt to the centre of the body influenced the adjusting of the seat belt in the right front seat. 2.5 Survivability Although all the occupants were found released from their personnel restraints, and since no information to the contrary exists, it is most probable that the passengers would have used the seat belts at take-off, during flight, and on landing. Notwithstanding that the doors were functional and without defect, it could not be determined why the occupants did not escape from the aircraft. However, when the aircraft overturned and rapidly sank, it is probable that the occupants became disoriented in the dark and frigid water and panicked. In addition to these factors, the confined and inverted cabin would have made the normally easy action of locating and operating the door handles a most challenging task, especially after undoing their seat belts and, thereby, further losing reference to their relative locations. Had the pilot been trained in or exposed to underwater evacuation techniques, he may have escaped, and at the same time, he may have assisted others in escaping from the inverted aircraft cabin. 3.0 Conclusions 3.1 Findings The pilot was licenced and qualified in accordance with existing regulations. Maintenance records indicate that the aircraft was certificated, equipped, and maintained in accordance with existing regulations and approved procedures. No indication was found of any malfunction or pre-existing mechanical defect with the aircraft, its engine, or its systems that could have contributed to the accident. The aircraft's weight and centre of gravity were calculated to have been within certificated limits. The prevailing weather and water conditions at Kincolith are frequently challenging and increase the level of risk for aircraft operations into Kincolith. Conflicting wind and water conditions at the time of the occurrence was a factor which contributed to the accident. Direct radio communication between the Kincolith agent and arriving aircraft was not operational at the time of the accident. During the period when the Kincolith agent was waiting for the aircraft at the dock, direct communication between the agent and the operator's dispatch office in Prince Rupert was not possible. While the accident aircraft was landing at Kincolith, direct communication between the pilot and the Prince Rupert dispatch office was intermittent and not assured. The rudder trim was found in the nearly full-right position; it could not be determined if or when the pilot selected this setting. The passenger occupying the right front seat most likely slipped out of the personnel restraint when the aircraft nosed over. The adjustment for the lap belt of the right front seat was incorrect and diminished the efficacy of the shoulder belt. Although sufficient life jackets were onboard, neither the pilot nor passengers were wearing life jackets. The aircraft doors were functional and opened without difficulty during tests after the accident. The impact forces were survivable. It could not be determined why the occupants did not escape from the aircraft. Research shows that escape from an aircraft, overturned in the water, is infrequent, hazardous, and difficult. No existing Canadian regulations require floatplane operators to provide underwater escape training for pilots and cabin attendants. 3.2 Causes On touchdown, the float(s) struck the water and caused a flying attitude that the pilot could not control before the right wing dug in and the aircraft overturned. Contributing to the accident were conflicting wind and water conditions at the time of the occurrence. 4.0 Safety Action 4.1 Action Taken 4.1.1 Escape from a Submerged Seaplane It was determined that the occupants were restrained during the initial impact and rollover, and the impact forces were tolerable and survivable. The aircraft's doors were functional and opened without difficulty. It could not be determined why the occupants did not escape from the aircraft. The TSB identified 24 fatal seaplane accidents in Canada between 1 January 1990 and 1 July 1999 in which the flight terminated in water. These accidents resulted in 43 fatalities. In 29 of them, egress from the aircraft had not been achieved. Of these 29 fatalities, 23 did not occur on impact. Eleven of these 23 fatalities had sustained serious injuries during the accident impact. A physical impediment to egress, such as damaged exits or cargo blocking an exit, was a factor in 9 of these 23 fatalities. (These factors are not mutually exclusive.) Of these 23 fatalities, 7 did not have serious impact injuries and exits were not blocked. About half of the accidents and fatalities involved commercial operators. The annual accident rate was fairly constant during this time period, and the accidents were not concentrated in any particular geographic location. The psychological and physiological challenges associated with escaping from a submerged seaplane can be profound and can include the need to quickly locate, reach, and open an unfamiliar exit in cold dark water and in an inverted and distorted cabin while suffering from shock and injury. However, physical impediments associated with escaping from a submerged seaplane are often surmountable. It is likely that many people do not escape because they are not prepared to do so. In 1993, the TSB released Safety Study of Piloting Skills, Abilities, and Knowledge in Seaplane Operations (report number SSA93001) which examined 1,432 seaplane accidents. Although the study did not focus on survivability issues, it did compare the ratio of fatal accidents to total accidents for float-equipped aircrafts to that for wheel-equipped aircrafts (for makes and models of aircrafts most frequently float-equipped). For airplanes that were on wheels, 10% of the accidents were fatal, but when on floats, 17% were fatal. The study made 10 safety recommendations aimed at reducing the number of seaplane accidents. In addition, the TSB released Safety Study of Survivability in Seaplane Accidents (report SS9401) in 1994. To enhance survivability in seaplane accidents, six safety recommendations were made. Despite the actions taken in response to both sets of recommendations, the number of seaplane accidents has remained fairly constant and the ratio of fatal seaplane accidents to total seaplane accidents has increased. A requirement exists for aircrafts to be equipped with occupant restraint systems. These systems reduce the likelihood of injury on impact, thus increasing the chances of egress. Also, commercial operators are required to provide pre-flight safety briefings to passengers which include information on the location and operation of exits. Despite these defences against occupants not escaping from a submerged seaplane following a crash, accident histories indicate that the risk of drowning due to inadequate preparation for escape is still high. Given some unnecessary risk associated with underwater egress from crashed seaplanes and the apparent lack of initiatives within the seaplane community to address the issue, on 02 March 2000, the TSB issued Aviation Safety Advisory A000003-1 to TC. It suggested that TC consider reviewing the previous safety recommendations contained in the TSB safety studies in order to develop effective measures that would enhance the likelihood of escape from cabins of submerged seaplanes.